The fill-region function is going outside the region and giving an
error.  A  sample input and backtrace are attached.

Also attached is a patch to fill.el which fixes the problem.

Cheers,
Uday Reddy

----

If Emacs crashed, and you have the Emacs process in the gdb debugger,
please include the output from the following gdb commands:
    `bt full' and `xbacktrace'.
If you would like to further debug the crash, please read the file
d:/gnu/emacs-23.1/etc/DEBUG for instructions.


In GNU Emacs 23.1.1 (i386-mingw-nt5.1.2600)
 of 2009-07-30 on SOFT-MJASON
Windowing system distributor `Microsoft Corp.', version 5.1.2600
configured using `configure --with-gcc (4.4)'

Important settings:
  value of $LC_ALL: nil
  value of $LC_COLLATE: nil
  value of $LC_CTYPE: nil
  value of $LC_MESSAGES: nil
  value of $LC_MONETARY: nil
  value of $LC_NUMERIC: nil
  value of $LC_TIME: nil
  value of $LANG: ENU
  value of $XMODIFIERS: nil
  locale-coding-system: cp1252
  default-enable-multibyte-characters: t

Major mode: Editable Dired

Minor modes in effect:
  savehist-mode: t
  tooltip-mode: t
  mouse-wheel-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  global-auto-composition-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  line-number-mode: t
  transient-mark-mode: t

Recent input:
f i l l - r e g SPC <return> C-x u C-x u C-x u C-p 
C-SPC C-n C-n C-n C-n M-x f i l l - r e g SPC <return> 
C-x u C-x u C-x u C-x u C-x u C-x u C-x u C-x u q <switch-frame> 
<down-mouse-1> <mouse-movement> <mouse-1> C-x b <return> 
C-x b <return> C-x C-f f i l l . e SPC <return> C-s 
d e f u n SPC f i l l SPC - <backspace> <backspace> 
- r e g i o n C-s C-a <escape> C-x <switch-frame> <down-mouse-1> 
<mouse-movement> <mouse-1> C-a C-SPC C-n C-n C-n C-n 
M-x f i l l - r e g SPC <return> q C-x u M-x v m - 
s u b C-g C-x C-f <backspace> <return> g <up> <up> 
n M-x C-g s M-x w d i r e d - SPC <return> C-p C-p 
C-a C-x q v m - b u g - E l i - f i l l i n g <return> 
e m a c s - b u g - f i l l i n g C-g M-x w d i r e 
d C-g C-x q v m - b u g - E l i - f i l l i n g - r 
e p l i e s - 2 <return> e m a c s - b u g - f i l 
l i n g <return> SPC C-a C-x q <up> <up> C-n <backspace> 
<backspace> <return> <up> <up> <return> SPC SPC SPC 
SPC SPC SPC M-x s u b m i t - b u SPC SPC <backspace> 
<backspace> <backspace> <backspace> <backspace> <backspace> 
<backspace> <backspace> <backspace> r e p o r t SPC 
e m SPC SPC <return>

Recent messages:
Entering debugger...
Back to top level.
Undo in region!
Quit [2 times]
Press C-c C-c when finished or C-c ESC to abort changes
Quit [2 times]
Mark set
Replaced 1 occurrence
Mark set
Replaced 6 occurrences